<!-- <style>
    p {
        
    }
</style> -->

<!-- <!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <link rel="stylesheet" href="./style.css">
</head>
<body>
    <div>hello world</div>
</body>
</html> -->

<!-- <style>
    .box {
        width: 200px;
        height: 150px;
    }

    .red {
        background-color: red;
    }

    .green {
        background-color: green;
    }
</style>
<div class="box red"></div>
<div class="box green"></div>
<div class="box red"></div> -->

<!-- <style>
    #ha {
        color: red;
    }
</style>
<div id="ha">蛤蛤蛤</div> -->


<!-- <style>
    li>a {
        color: red;
    }
</style>
<div class="cat">
    <ul>
        <li><a href="#">小猫</a></li>
        <li><a href="#">小猫</a></li>
        <li><a href="#">小猫</a></li>
        <li>
            <p><a href="#">小猫</a></p>
        </li>
    </ul>
</div> -->

<!-- <style>
    div a{
        color: red;
    }
</style>
<div class="cat">
    <a href="#">小猫</a>
    <ul>
        <li><a href="#">小狗</a></li>
        <li><a href="#">U·ェ·U</a></li>
    </ul>
</div> -->

<!-- <style>
    a:link {
        color: black;
        /* 去掉 a 标签的下划线 */
        text-decoration: none;
    }

    a:visited {
        color: green;
    }

    a:hover {
        color: red;
    }

    a:active {
        color: blue;
    }
</style>
-->

<!-- <style>
    a {
        color: black;
    }

    a:hover {
        color: red;
    }
</style>

<a href="#">小猫</a> -->

<!-- <!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        #n {
            font-family: '微软雅黑';
            font-size: 50px;
            font-weight: 100;
            font-style: normal;
        }
    </style>
</head>

<body id="n">
    <em>
        你好啊！！！
    </em>
</body>

</html> -->

<!-- <style>
p{
    color: red;
    color: #ff0000;
    /*其中ff表示红色像素点，00表示绿色像素点，00表示蓝色像素点*/
    color: rgb(255, 0, 0);
}
</style> -->

<!-- <style>
    .text-align .one {
        text-align: left;
   }
    .text-align .two {
        text-align: right;
   }
    .text-align .three {
        text-align: center;
   }
</style>
<div class="text-align">
    <div class="one">左对齐</div>
    <div class="two">右对齐</div>
    <div class="three">居中对齐</div>
</div> -->


<!-- <style>
    .text-indent .one {
        text-indent: 2em;
   }
    .text-indent .two {
        text-indent: -2em;
   }
</style>
<div class="text-indent">
    <div class="one">正常缩进</div>
    <div class="two">反向缩进</div>
</div> -->

<!-- <style>
    .line-height .one {
        line-height: 40px;
        font-size: 16px;
   }
</style>
<div class="line-height">
    <div>
       上一行
    </div>
    <div class="one">
       中间行
    </div>
    <div>
       下一行
    </div>
</div> -->

<style>
    .line-height .two {
        height: 100px;
        line-height: 100px;
   }
</style>
<div class="line-height">
    <div class="two">
       文本垂直居中
    </div>
</div>